Life cycle assessment (LCA) looks at the environmental impacts of a building material over the entire life of the material, from extraction to disposal. LCA attempts to quantify these impacts for the purpose of comparing materials or buildings.
What is measured?
LCA is a scientific study of the environmental inputs and outputs to a building material, product, or a whole building throughout its life. Several environmental effects are studied in each assessment, including:
- Use of fossil fuels
- Use of non-renewable resources
- Water use
- Global warming potential
- Stratospheric ozone depletion
- Ground level ozone (smog) creation
- Effect on water bodies and organisms
- Acidification and acid deposition
- Toxic releases to air, water and land
Some of these effects cannot be exactly quantified for a specific unit of material, so estimates are used. The importance of LCA is not necessarily in the quantification of specific environmental effects, but in the comparison of products and assemblies.
Stages of Life
The life of a building material can be broken down into five phases:
- Resource extraction